You search for a good and efficient HiFi Tube Amplifier emulation?
You've got it. TubeDriver internal structure is truly efficient, woww! Try the last updated version (v1.3): Same as v1.22 with two more parameters :
THD(total harmonics distorsion) vu metering and Mix/Wet function.

I use this plugin as a pre-amp when I record vocals and acoustic instruments. I like how it shapes the sound for me. It's one of my three go-to plugin when recording along with Eventide's UltraChanel and Nick Crow's Wagner Sharp.